Process for coloring organic solvents, mineral oil products, waxes, plastics and surface coatings with cyano-nitro-amino-azo dyes

ABSTRACT

Dyestuffs of the formula ##STR1## are used for coloring organic solvents, mineral oil products, waxes, plastics and surface coatings, wherein R is alkyl having 1 to 7 carbon atoms, R 1  is alkyl having 1 to 8 carbon atoms or alkenyl having 3 or 4 carbon atoms, and R 2  is hydrogen, alkyl having 1 to 8 carbon atoms or alkenyl having 3 or 4 carbon atoms.

The invention relates to a process for colouring organic solvents, mineral oil products, waxes, plastics and surface coatings, which is characterised in that dyestuffs of the general formula I ##STR2## are used, in which R denotes alkyl having 1 to 7 C atoms and R¹ and R² independently of one another denote alkyl having 1 to 8 C atoms or alkenyl having 3 or 4 C atoms and R² additionally denotes hydrogen.

Examples of alkyl radicals represented by R¹ and R² are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec.-butyl, n-pentyl, 2- and 3-methylbutyl, n-hexyl, n-heptyl and 2-ethylhexyl.

Alkenyl radicals represented by R¹ and R² are allyl, crotyl and methallyl.

Preferred radicals for R¹ and R² are ethyl, n-propyl, n-butyl, isobutyl and allyl.

Examples of alkyl radicals represented by R are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec.-butyl, tert.-butyl, n-phentyl, pent-3-yl, n-hexyl and hept-3-yl.

Preferred radicals for R have 3 to 7 C atoms, such as, for example, n-propyl, isopropyl, n-butyl, isobutyl, sec.-butyl pent-3-yl or hept-3-yl. Particularly preferred alkyl radicals for R have 3 C atoms, in particular n-propyl.

Preferred dyestuffs for the process according to the invention have the formula I in which R² has the same meaning as R¹. In particular those dyestuffs of the formula I are preferred in which R¹ is identical to R² and denotes ethyl, n-propyl, n-butyl, isobutyl or allyl and R has the abovementioned ideally preferred meanings.

Preferred dyestuffs of the formula I are also those in which R denotes methyl or ethyl and the total number of carbon atoms in the 3 radicals R, R¹ and R² is at least 7, that is to say equal to 7 or larger than 7. Particularly preferred are dyestuffs of this type in which additionally R¹ is identical to R². Preferred dyestuffs of the formula I are also those in which R¹ denotes isopropyl or secondary alkyl having 4 to 8 C atoms and R² denotes hydrogen and the total number of carbon atoms in the radicals R¹ and R² is at least 7. Very particularly preferred is the dyestuff of the formula I in which R=n-propyl and R¹ =R² =ethyl.

The dyestuffs of the general formula I can be prepared in a manner which is in itself known by diazotising an amine of the formula II: ##STR3## in which X represents cyano or halogen and Y represents halogen and halogen can be chlorine, bromine or iodine, coupling the resulting diazo compound with an amine of the formula III: ##STR4## and replacing X and/or Y, insofar as it represents halogen, in the resulting compound of the general formula IV: ##STR5## by cyano, as described, for example in the following German Offenlegungsschriften Nos. 1,544,563, 2,310,745, 2,456,495, 2,610,675, 2,724,116, 2,724,117, 2,834,137, 2,834,386, 2,846,438, 2,915,072 and 2,931,081.

Furthermore, the dyestuffs to be used according to the invention can also be prepared in line with the teaching of Czech Pat. No. 164,657 by diazotising the amine of the formula V: ##STR6## and coupling the diazo compound to an amine of the formula III, and advantageously freeing the dyestuff thus obtained from byproducts by crystallisation.

Some of the dyestuffs of the general formula I are known as disperse dyestuffs, in particular for dyeing polyester fibres, and are described, for example, in German Offenlegungsschrift No. 1,963,735 and in German Offenlegungsschrift No. 2,928,432.

It has now been found, surprisingly, that these dyestuffs are highly suitable for colouring organic solvents, mineral oil products, waxes, plastics and surface coatings since they have an unexpectedly high solubility, high colour intensity and good fastness properties, in particular good light-fastness, in these media.

Examples of organic solvents which can be coloured by means of dyestuffs of the formula I are alcohols, such as, for example, ethanol, propanol, isopropanol, butanol, isobutanol or tert.-butanol, esters, such as, for example, ethyl, propyl or butyl acetate, methoxyethyl acetate, dibutyl phthalate or diethylhexyl phthalate, ketones, such as, for example, acetone, methyl ethyl ketone or diethyl ketone, glycols and glycol ethers, such as, for example, methylglycol, ethylglycol, methyldiglycol or butyldiglycol and aromatic hydrocarbons, such as, for example, toluene or xylenes. Products which contain the abovementioned substrates and which can therefore be coloured by means of dyestuffs of the formula I are, for example, printing inks, writing inks and varnishes, such as, for example, transparent varnishes for flexographic printing. Examples of colourable mineral oil products are diesel oil and fuel oil. Examples of plastics which can be mass-coloured are polyvinyl chloride, styrene-butadiene mixtures and acrylonitrile-butadiene mixtures, but above all polyolefines such as polyethylene, polypropylene and preferably polystyrene. Mass-colouring of the plastics mentioned produces in a manner which is in itself known colourings of high colour intensities and excellent fastness properties, in particular excellent light- and weathering-fastness.

In the process according to the invention, it is also possible to use mixtures of two or more of the dyestuffs of the formula I. Here as a rule the proportion of the individual dyestuffs in the mixture is 10 to 90 percent by weight.

In the examples which follow parts denote parts by weight.

EXAMPLE 1

5 parts of the dyestuff of the formula: ##STR7## are dissolved in a mixture of 37 parts of ethyl acetate, 37 parts of methyl ethyl ketone and 20 parts of a vinyl chloride/vinyl acetate copolymer (as binder). A blue-coloured varnish is obtained which is suitable as a surface coating, for example for aluminium foil.

The dyestuff can be prepared as follows: 18.0 g of copper(I) cyanide are stirred for 15 minutes at room temperature with 2.0 g of sodium cyanide in 150 ml of dimethylformamide. 54.1 g of the dyestuff of the formula: ##STR8## are then added, and the mixture is heated for 15 minutes at 110° C. to 115° C. Stirring is continued until the mixture has cooled down, and the product is filtered off with suction, washed with 20 ml of dimethylformamide, water, 5% strength aqueous ammonia and again with water and dried under reduced pressure.

EXAMPLE 2

10 parts of the dyestuff mentioned in Example 1 are dissolved in 200 parts of toluene. The blue solution is allowed to flow with stirring into 2,000,000 parts of fuel oil which is thus coloured blue.

EXAMPLE 3

3 parts of the dyestuff mentioned in Example 1 are dissolved in 67 parts of ethanol, 10 parts of propanol and 10 parts of ethylglycol and 10 parts of a styrene/maleic acid resin are admixed as binder. This produces a blue alcoholic ink for writing implements.

EXAMPLE 4

3 parts of the dyestuff of Example 1 are dissolved in a mixture of 86 parts of toluene and 11 parts of a styrene-maleate resin. This produces a blue ink for felt tip pens.

EXAMPLE 5

0.5 part of the dyestuff mentioned in Example 1 are dissolved in a mixture of 8 parts of n-butanol, 4 parts of diethylhexyl phthalate, 4 parts of dibutyl phthalate, 34 parts of toluene, 35 parts of ethylglycol and 15 parts of collodion cotton. This solution is used to print white paper. After drying, an intensely coloured blue print which has good fastness properties is obtained.

EXAMPLE 6

0.5 part of the dyestuff mentioned in Example 1 is mixed with 1,000 parts of polystyrene granules or powder. The resulting mixture is melted and the dyestuff dissolves. Solidification produces polystyrene material which is coloured deep blue and has excellent light-fastness.

In the same way as in Examples 1 to 6 it is possible to use the dyestuffs which are characterised in the table below by specification of their substituents.

    ______________________________________                                          ##STR9##                                                                      R         R.sup.1        R.sup.2      Hue                                      ______________________________________                                         C.sub.2 H.sub.5                                                                          C.sub.2 H.sub.5                                                                               C.sub.2 H.sub.5                                                                             blue                                     C.sub.2 H.sub.5                                                                          n-C.sub.4 H.sub.9                                                                             n-C.sub.4 H.sub.9                                                                           blue                                     C.sub.2 H.sub.5                                                                          CH(CH.sub.2 H.sub.5)C.sub.4 H.sub.9                                                           H            red-                                                                           dish                                                                           blue                                     C.sub.2 H.sub.5                                                                          CH.sub.2 CH(CH.sub.3).sub.2                                                                   C.sub.2 H.sub.5                                                                             blue                                     C.sub.2 H.sub.5                                                                          CH.sub.2 CHCHCH.sub.3                                                                         CH.sub.2 CHCHCH.sub.3                                                                       blue                                     n-C.sub.3 H.sub.7                                                                        CH.sub.2 CHCH.sub.2                                                                           CH.sub.2 CHCH.sub.2                                                                         blue                                     n-C.sub.3 H.sub.7                                                                        n-C.sub.3 H.sub.7                                                                             n-C.sub.3 H.sub.7                                                                           blue                                     n-C.sub.3 H.sub.7                                                                        n-C.sub.4 H.sub.9                                                                             n-C.sub.4 H.sub.9                                                                           blue                                     n-C.sub.3 H.sub.7                                                                        CH(CH.sub.3)C.sub.2 H.sub.5                                                                   H            red-                                                                           dish                                                                           blue                                     n-C.sub.3 H.sub.7                                                                        CH.sub.3       CH.sub.2 CHCH.sub.2                                                                         blue                                     n-C.sub.3 H.sub.7                                                                        CH(CH.sub.3).sub.2                                                                            C.sub.2 H.sub.5                                                                             blue                                     n-C.sub.3 H.sub.7                                                                        n-C.sub.6 H.sub.13                                                                            n-C.sub.6 H.sub.13                                                                          blue                                     i-C.sub.3 H.sub.7                                                                        C.sub.2 H.sub.5                                                                               C.sub.2 H.sub.5                                                                             blue                                     i-C.sub.3 H.sub.7                                                                        n-C.sub.3 H.sub.7                                                                             n-C.sub.3 H.sub.7                                                                           blue                                     i-C.sub.3 H.sub.7                                                                        i-C.sub.4 H.sub.9                                                                             i-C.sub.4 H.sub.9                                                                           blue                                     i-C.sub.3 H.sub.7                                                                        CH(CH.sub.3)C.sub.3 H.sub.7                                                                   CH.sub.2 CHCH.sub.2                                                                         blue                                     i-C.sub.3 H.sub.7                                                                        n-C.sub.5 H.sub.11                                                                            n-C.sub.5 H.sub.11                                                                          blue                                     n-C.sub.4 H.sub.9                                                                        CH.sub.3       CH.sub.3     blue                                     n-C.sub.4 H.sub.9                                                                        n-C.sub.3 H.sub.7                                                                             n-C.sub.3 H.sub.7                                                                           blue                                     n-C.sub.4 H.sub.9                                                                        i-C.sub.3 H.sub.7                                                                             C.sub.2 H.sub.5                                                                             blue                                     n-C.sub.4 H.sub.9                                                                        CH(C.sub.2 H.sub.5).sub.2                                                                     H            red-                                                                           dish                                                                           blue                                     CH(CH.sub.3).sub.3                                                                       C.sub.2 H.sub.5                                                                               C.sub.2 H.sub.5                                                                             red-                                                                           dish                                                                           blue                                     CH(CH.sub.3).sub.3                                                                       n-C.sub.4 H.sub.9                                                                             n-C.sub.4 H.sub.9                                                                           red-                                                                           dish                                                                           blue                                     CH.sub.2 CH(CH.sub.3).sub.2                                                              C.sub.2 H.sub.5                                                                               C.sub.2 H.sub.5                                                                             blue                                     CH.sub.2 CH(CH.sub.3).sub.2                                                              CH.sub.2 CHCH.sub.2                                                                           CH.sub.2 CHCH.sub.2                                                                         blue                                     CH.sub.2 CH(CH.sub.3).sub.2                                                              CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9                                                            H            red-                                                                           dish                                                                           blue                                     CH(CH.sub.3)C.sub.2 H.sub.5                                                              CH.sub.3       CH.sub.3     blue                                     CH(CH.sub.3)C.sub.2 H.sub.5                                                              n-C.sub.3 H.sub.7                                                                             n-C.sub.3 H.sub.7                                                                           blue                                     CH(CH.sub.3)C.sub.2 H.sub.5                                                              n-C.sub.5 H.sub.11                                                                            n-C.sub.5 H.sub.11                                                                          blue                                     CH(CH.sub.3)C.sub.2 H.sub.5                                                              C.sub.2 H.sub.5                                                                               CH.sub.2 CHCH.sub.2                                                                         blue                                     n-C.sub.5 H.sub.11                                                                       C.sub.2 H.sub.5                                                                               C.sub.2 H.sub.5                                                                             blue                                     n-C.sub.5 H.sub.11                                                                       CH.sub.2 CHCH.sub.2                                                                           CH.sub.2 CHCH.sub.2                                                                         blue                                     n-C.sub.5 H.sub.11                                                                       CH(CH.sub.3)C.sub.2 H.sub.5                                                                   H            red-                                                                           dish                                                                           blue                                     CH(C.sub.2 H.sub.5).sub.2                                                                C.sub.2 H.sub.5                                                                               C.sub.2 H.sub.5                                                                             blue                                     CH(C.sub.2 H.sub.5).sub.2                                                                n-C.sub.4 H.sub.9                                                                             n-C.sub.4 H.sub.9                                                                           blue                                     CH(C.sub.2 H.sub.5).sub.2                                                                CH.sub.2 CHCH.sub.2                                                                           CH.sub.2 CHCH.sub.2                                                                         blue                                     CH(C.sub.2 H.sub.5).sub.2                                                                i-C.sub.4 H.sub.9                                                                             C.sub.2 H.sub.5                                                                             blue                                     CH(C.sub.2 H.sub.5).sub.2                                                                CH(CH.sub.3)C.sub.2 H.sub.5                                                                   H            red-                                                                           dish                                                                           blue                                     n-C.sub.6 H.sub.13                                                                       C.sub.2 H.sub.5                                                                               C.sub.2 H.sub.5                                                                             blue                                     CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9                                                       C.sub.2 H.sub.5                                                                               C.sub.2 H.sub.5                                                                             blue                                     CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9                                                       CH.sub.2 CHCH.sub.2                                                                           CH.sub.2 CHCH.sub.2                                                                         blue                                     CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9                                                       CH.sub.2 CH(CH.sub.3)CH.sub.2                                                                 H            red-                                                                           dish                                                                           blue                                     CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9                                                       n-C.sub.4 H.sub.9                                                                             n-C.sub.4 H.sub.9                                                                           blue                                     CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9                                             CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9                                                       CH(C.sub.2 H.sub.5).sub.2                                                                     H            red-                                                                           dish                                                                           blue                                     CH.sub.3  n-C.sub.4 H.sub.9                                                                             n-C.sub.4 H.sub.9                                                                           blue                                     CH.sub.3  n-C.sub.6 H.sub.13                                                                            n-C.sub.6 H.sub.13                                                                          blue                                     CH.sub.3  CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9                                                            H            red-                                                                           dish                                                                           blue                                     CH.sub.3  CH(C.sub.2 H.sub.5).sub.2                                                                     CH.sub.2 CHCH.sub.2                                                                         red-                                                                           dish                                                                           blue                                     ______________________________________                                    

The organic solvents, mineral oil products, waxes, plastics and surface coatings are coloured with the dyestuffs of formula I by mixing these materials in liquid, molten or thermoplastic state, for example at temperatures from 0°-250° C., preferably from 10°-240° C., with one or several dyestuffs of formula I, the colouring of the substrate being effected, with rapid dissolution of the dyestuff or dyestuffs, within a period ranging from a few seconds to a few minutes. Substrates which are to be coloured and which are liquid at ambient temperature, such as organic solvents, mineral oil products (benzines, gasoline, petrol, diesel oils, fuel oils etc.), surface coatings (lacquers, varnishes, paints etc.) are mixed with the dyestuff of formula I at, as a rule, temperatures from 10°-30° C., preferably at ambient temperature. Waxes, in most cases, melt at temperatures from 50°-90° C. and are therefore, as a rule, mixed with the dyestuffs of formula I at these temperatures. In the case of liquid substrates the dyestuff or dyestuff mixture is, as a rule, mixed with the liquid or molten substrate by simple stirring in.

The colouring of plastics, in particular of polystyrene, can take place in various phases of their process of preparation, for example colouring the monomers prior to polymerisation, polycondensation or polyaddition. Normally however, thermoplastics are mixed and thus coloured in their thermoplastic state, for example on the roll mill, in the screw kneader, extruder or screw extruder, with the dystuff or dyestuff mixture at temperatures up to 250° C., preferably up to 240° C. During this operation, plasticizers, stabilizers, lubricants and/or other auxiliaries can be simultaneously incorporated into the plastics. Subsequently, the coloured plastics is granulated in a manner known by itself and is passed on to the final consumer. Thermoplastics can also be coloured by the final consumer using the so-called dry-colouring process. In this process, colourless plastic granules are mixed with the dyestuff or dyestuff mixture in a dry state and are subsequently processed in the injection moulding machine to give coloured injection moulded parts.

Depending on the depth of color desired, 0.001 to 10, preferably 0.002 to 5 parts by weight of the dyestuff or dyestuff mixture are employed per 1,000 parts by weight of substrate. In most cases it is appropriate not to mix the dyestuff or dyestuff mixture directly into the substrate to be coloured but to prepare first a so-called batch, i.e. a concentrated solution or pre-mixture and to subsequently mix said batch into the substrate to be coloured. The concentration of the dyestuff or dyestuff mixture in the batch is selected to be as high as possible and is, as a rule, 10 to 50 percent by weight, preferably 30 to 50 percent by weight. If the carrier substance used for the batch is an organic solvent, a mineral oil product which is liquid at ambient temperature or a different liquid product, the batch is prepared by stirring the dyestuff into the liquid product. If said carrier substance is a plastics the batch is coloured as described above in connection with the colouring of plastics, with the exception that the dyestuff concentration used for preparing the batch is selected to be correspondingly higher. It goes without saying that the organic solvents, mineral oil products, waxes, plastics and surface coatings to be coloured by the process of the invention can also contain further substances such as extenders or fillers, pigments, auxiliaries, stabilizers, resins and the like. 

What is claimed is:
 1. The process for coloring a material selected from benzine, gasoline, petrol, diesel oil, fuel oil, waxes, polyvinyl chloride, polyethylene, polypropylene, polystyrene, polymers of styrene-butadiene mixtures or acrylonitrile-butadiene mixtures, lacquers, varnishes or paints which comprises mixing said material in liquid, molten or thermoplastic state at temperatures from 0° to 250° C. with a color producing amount of a dyestuff of the formula ##STR10## wherein R is alkyl having 1 to 7 carbon atoms; R¹ is alkyl having 1 to 8 carbon atoms or alkenyl having 3 or 4 carbon atoms; R² is hydrogen, alkyl having 1 to 8 carbon atoms or alkenyl having 3 or 4 carbon atoms.
 2. The process according to claim 1 wherein said material to be colored is selected from waxes and is colored in molten state at temperatures of 50° to 90° C.
 3. The process according to claim 1 wherein said material to be colored is selected from lacquers, varnishes or paints and is colored at temperatures of 10° to 30° C.
 4. The process according to claim 1 wherein said material to be colored is polystyrene.
 5. The process according to claim 1 wherein R¹ and R² are identical.
 6. The process according to claim 1 or claim 2 wherein each of R¹ and R² is ethyl, n-propyl, n-butyl, isobutyl or allyl.
 7. The process according to claim 1 wherein R is alkyl having 3 to 7 carbon atoms.
 8. The process according to claim 7 wherein R is alkyl having 3 carbon atoms.
 9. The process according to claim 8 wherein R is n-propyl.
 10. The process according to claim 1 wherein each of R¹ and R² is ethyl and R is n-propyl.
 11. The process according to claim 1 wherein the dyestuff comprises mixtures of two or more species of said formula with the proportion of the individual species in the mixture being 10 to 90 percent by weight.
 12. The process according to claim 1 wherein R is methyl or ethyl and the total number of carbon atoms in R, R¹ and R² is at least
 7. 13. The process according to claim 1 wherein R¹ is isopropyl or secondary alkyl having 4 to 8 carbon atoms, R² is hydrogen, and the total number of carbon atoms in R¹ and R is at least
 7. 